The lawmakers outlined their concerns in a letter to White House general counsel Don McGahn on Wednesday.

“While the various congressional and law enforcement investigations continue, the White House should take all possible steps to protect national security including immediately revoking Mr. Kushner’s security clearance,” the letter read.

That request, if granted, would be an extraordinary step in the ongoing congressional investigation of the Trump campaign’s communications with Russia — and the FBI’s inquiry of Kushner’s talks with the Kremlin, which have gained greater significance in recent weeks.

Kushner, President Donald Trump’s son-in-law and top White House adviser, was willing to go extraordinary lengths to establish a secret line of communication between the Trump administration and Russian government officials, The Washington Post reported on Friday.

During the presidential transition period leading up to Trump’s inauguration, Kushner held a series of meetings with the Russian ambassador to the US, Sergey Kislyak, and the head of a Moscow bank that was under US sanctions.

In talks with Kislyak in December, Kushner floated the possibility of setting up a secure line of communication between the Trump transition team and Russia — and having those talks take place in Russian diplomatic facilities in the US, essentially concealing their interactions from US government scrutiny.

“Jared Kushner cannot be trusted,” said Rep. Don Beyer of Virginia, who also signed the letter.

The Trump administration has downplayed concerns about Kushner’s talks with the Russians. US intelligence officials have said Kushner is not accused of any wrongdoing.